Manufacture of shaped castings of ferrosilicid.



N. G. PETINOT.

MANUFACTURE OF SHAPED CASTINGS 0F FERROSILICID.

APPLICATION FILED DEC. 19. I917.

Patented July 30, 1918.

IIVI/E/VTOR 19 A TTORIVEVS UNITED STATES PATENT OFFICE.

NAPOLEON G. PETINOT, OF NEW YORK, N. Y., ASSIGNOR TO UNITED STATES ALLOYS CORPORATION, OF NEW YORK. N. Y., A CORPORATION OF NEW YORK.

MANUFACTURE OF SHAPED CASTINGS OF FERROSILICID.

Specification of Letters Patent.

rammed July so, 1918.

continuation in part of application Serial No. 110,038, filed July 19, 1916. This application filed December 19, 1917. Serial No. 207,829.

, To all whom it may concern.

Be it known that I, NAPOLEON G. PFIIINOT, a citizen of the United States, and resident of the city of New York, county of New York, and State of New York, have made a certain new and useful Invention Relating to the Manufacture of Shaped Castings of F errosilicid, of which the following is a specification.

The invention relates particularly to the manufacture of shaped castings of an alloy of iron and silicon approximating an iron silicid which would be represented by the formula Fe Si.

This alloy of iron and silicon I manufac ture and directly employ in the making of shaped castings. The alloy may be considered also as consisting of a solid solution of iron and a silicid Fe Si containing thirteen and ninety-hundredths per cent. (13.90%) of silicon or a solid solution of iron and some other definite silicid, I havefound that an iron and silicon alloy with a content of silicon approximating from ten per cent. (10%) to sixteen per cent. (16%) will answer the same purpose for castings and will be referred to simply as an iron silicid.

Such iron silicid can be readily molded when in a fluid condition into shaped castings. Through the microscope it appears as formed of small prismatic crystals having a metallic appearance. It is magnetic and has a specific gravity of 7. It is not attacked by either dilute or concentric nitric or sulfuric acid. It is dissolved by hydrochloric acid, also by hydrofluoric acid. In an alkaline solution the alloy is attacked.

An object of the present invention is to produce a molten iron silicid of Fe Si or a molten solid solution consisting of iron and an iron silicid, in which solution the silicon approximates from ten percent. (10%) to sixteen per cent. (16%), and to pour said solution while in a molten condition into a shaped mold so as to produce a desired cast- I have found that in the furnace which I use for making the iron silicid the amount which can be tapped from time to time is limited. Thus using a furnace of 750 kilowatt capacity I can *tap about 2,000 pounds of the iron silicid every hour, and it isnot practicable to construct the furnace the furnace in which the iron silicid alloy is madelarge enough to make or accumulate therein an indefinitely large amount of the iron silicid alloy. The consequence of this is that when I desire to make large castings that weigh more than 2,000 pounds or when the aggregate weight of castings to be poured at any one time exceeds 2,000 pounds the 750 kilowatt furnace has not a sufficiently large capacity.

i To overcome this difficulty I use with the furnace an electric mixer or holder which serves as a storage for the iron silicid made in the electric furnace.

The present invention is also directed to a method whereby relatively large iron silicid castings, that is castings requiring a heavy weight or a large quantity of iron silicid, can be made of the product derived from a relatively small melting furnace by the employment of the electric mixer or holder which serves as a storage for the iron silicid produced in the electric furnace.

The present invention is in many respects a continuation of the subject matter embraced in my co-pending application Serial No. 110,038, filed July 19, 1916, entitled Invention relating to the manufacture of shaped castings of ferro-silicid.

In the accompanying drawing there are illustrated an electric melting furnace and an electric mixer which can be employed in performing the invention, the electric melting furnace being shown in Figure 1 and the electric mixer in Fig. 2.

In the performing of my invention the iron silicid Fe Si or the solid solution having the composition above referred to is produced directly in an electric arc melting furnace, preferably of the Siemens type, and it is a furnace of this type which is shown in cross-sectional view in Fig. 1.

In said Fig. 1 the reference character 1 designates a large metal plate which may be considered to constitute oneof the ter-' the bottom of a pocket 3 that serves as a 'receptacle for molten metals, to wit, the bath 4. As the coke layer is a conductor of electricity, it serves as a proper medium to conduct the electricity from the molten-bath 4. to the metal plate or terminal 1. There is embedded in, or placed upon, this layer of coke a trough or spout 5 having a tap hole 5 through which the metal in the bath can flow to the exterior of the furnace. A ver-' tically extending and vertically movable terminal or electrode 6 is located above the receptacle or receiving portion 3, or bath of molten metal 4;. Aroundthis electrode there is a wall 7 provided with a lining 8, the inner side of'which lining is defined, for example, by the lines 9, 9. Within the space between the electrode 6 and the lining 8 there is placed the charge 10 containing the materials to be treated in the furnace.

I use as a charge a mixture of iron scrap or iron oxid, quartz or silica sand and coke,

though in place of, or in conjunction with, the coke any carbonaceous material, such'as petroleum coke, coke, charcoal, anthraclte coal,- e-tc., can be used. Of course, in using mentioned will consistof an iron silicon or ature.

any particular carbonaceous material there must be taken into consideration the percentage of fixed carbon therein. The electricity is supplied to the furnace by the means diagrammatically illustrated and designated as 11.

In the normal operation of the furnace an arc is maintained between the lower end of the electrode 6 and the bath of molten metal 4, and the material in the charge which is in with the furnace in normal operation a reduction takes place which may be illustrated by the following formula and from this formula it will be readily ascertained that the reduction of 100 parts of silicon from 214. parts of pure silica requires 86 parts of carbon.

For instance, in practical work, I use 'in the charging a mixture such as the follow ing:-30 pounds of silica plus 20 pounds of coke "and 88 pounds of iron scrap. This mixture has a slight excess of coke over that required to theoretically complete chemical reaction. i v

As the operation proceeds the carbon in the coke reduces the silica so as to form CO and leave the silicon. .The iron scrap combines with the silicon, thus formed, lowering the temperature of reduction of the mix- It will here be noted that it takes about 1562 kilowatt hours per metric ton of metal produced.

The product resulting from the heating of the ingredients in the proportions above solid solution of iron and. an iron silicid FeO+C =Fe+CO and SiO +2C=Si+2CO The silicon (Si) and the iron (Fe) unite and the formula as a whole may be written I as follows:

In the practical performing of the invention, where iron oxid is employed, the following mixture is used:

30 pounds silica, 50 pounds coke and 125 pounds of iron oxid.-

In this mixture the coke is somewhat in excess of that required to theoretically re- The furnace can be operated in different p .ways; for instance, by keeping. the furnace charge continuouslyaround the electrode (or electrodes if there are more than one) so as to preventthe volatilization of the Si0 which condenses in the charge. The resulting liquid metal or solution in the receptacle or pocket in the furnace can be tapped at intervals in a receiving ladle, as is done with an ordinary iron cupola furnace.

If the furnace is of large capacity, 1000 H. P., for instance, the tap hole 5 in the trough or spout can be kept open and'the m'etal allowed to run continuously into the receiving. ladle. I

The composition of the metal, or resulting solution, which is produced in the furnace,

will vary slightly due, for instance, to the inability of the workmen to maintain the percentage of different ingredients in the charge absolutely uniform.

If a definite composition of the charge is desired, a sample of the molten metal from the furnace can be analyzed and the proper substances can be added to the bath of the furnace to rectify the composition of the bath, if necessary.

The iron silicid of iron and an iron silicid which contains a silicon content of from ten per cent. 10%) -to sixteen per cent. (16%), and {which as Fe Si orthe solid solution previously indicated is to be considered an iron silicid, can be readily formed into a shaped casting by pouring the material from the ladle into a mold having a definite shape and this is done while the material in the ladle still remains in a molten condition.

The iron (Fe) in the iron silicid (-viz., the alloy) might to some extent be replaced by other metals without materially altering or changing the chemical or physical characteristics of the alloy and it Will here be noted that any alloy which contains as base materials iron and silicon in approximately the proportions described will be the mechanical and chemical equivalent of the iron silicon alloy herein described.

The electric melting furnace illustrated is of the Siemens type andit is this type of furnace that I preferably employ in performing the invention. In some instances, according to the power available, it may be found convenient or preferable to use in stead other kinds of arc furnaces, for in-. stance furnaces of the one phase, two phase or multiple phase type.

As to the voltage employed, I prefer 30, 40 and 60 volts, though any voltage above this will give the same product with probably a little more volatillzation.

The lining of the furnace hearth can all be in carbon, or the bottom in carbon and the wall in silica-brick or fire-clay brick, since such a furnace as that illustrated makes its own lining with a molten charge. As to the holder previously referred to it will be noted that various forms of electric furnace may be used to constitute the electric mixer. For example, the Siemens furnace consisting of one electrode and a conducting hearth or the two electrode furnace of the common type known generally as the Hroult furnace, but I prefer to use as a mixer or holder a furnace supplied with three phase current and consequently three electrodes and the mixer furnace shown is of this latter type. This furnace is designated as 12 and consists of a tiltable iron shell 13 lined with silica brick and silica sand as in the ordinary acid open hearth furnace. The furnace has a roof 14 of silica brick with suitable openings as 15, 15 and 15 through which the electrodes 16, 16 and 16* pass. Each electrode is suitably carried as by an arm and is provided with a system of cables and pulleys operated by means of suitable winches, motors and other control apparatus. The furnace body is provided with one or more doors 17 of which one closes a suitable spout 18 through which molten metal can be either poured into or out of the furnace. The other doors are placed so that they permit convenient inspection of the inside of the furnace and also the patching or repairing bf the lining. The whole furnace is mounted on rockers 19 so that by means of an electric or hydraulicapparatus 20 it can be tilted for the purpose of pouring off a part or all of the molten charge.

' In carrying out my invention I tap the iron silicid from the electric melting furnace in which it is made and transfer to the electric mixer 12 where the alloy is kept hot by means of the electric current or is superheated by the same means to any desired temperature. As often as the furnace making the iron silicid is ta ped the metal is added to the charge contained in the electric mixer and the total amount is limited simply by the capacity of the mixer. Besides putting the molten iron silicid into the mixer I also introduce suitable slag forming materials sm, which will melt and form an acid slag covering the whole surface of the metal in the mixer and thus prevent oxidation. When making castings the metal is drawn from the mixer.

The advantages of my invention are that I can store any desired amount of iron silicid in a molten condition and keep it molten, or super-heat to any desired temperature. I can, moreover, ad ust the composition of the iron silicid with great exactness in the mixer by suitably varying the composition of the iron silicid as produced in the electric furnace used for its manufacture. The electric mixer also preserves exactly the composition of the iron silicid by means of the blanket of slag which covers the metal and protects it from oxidation. Finally, I can draw either small or large quantities of iron silicid from the mixer at any time and in any quantities as required for the shaped casting I desire to make.

Some of the advantages of employing the new process in the manufacture of an iron silicid containing from ten per cent. (10%) to sixteen per cent. (16%) silicon in an electric furnace for the direct production of castings are: (a) the direct production of the iron silicid in an electric furnace instead of employing a melting proposition which involves the melting of the constituents required, as is actually done in air furnaces or crucibles; (b) the production of a product low in sulfur and phosphorus, giving castings with better physical qualities than are available with the air furnace or crucible; and (c) the production of iron silicids in a reducing atmosphere under a blanket of silicious slag.

The manner of making a shaped casting by pouring the iron silicid into a previously and definitely formed mold, is apparent to any one skilled in the art of making shaped castings and therefore a further description as to this is believed to be unnecessary. Applicant believes he is the first to make an iron silicid casting having silicon of approximately ten per cent. (10%) to sixteen per cent. (16%) by directly forming the iron silicid in an electric furnace and pouring the resulting molten iron silicid into a previously shaped mold so as to form a casting of the desired shape and chemical constituents.

It will be manifest that the invention can be realized in various ways without departing from the spirit and scope thereof.

What I claim is:

1. In the manufacture of acid resisting shaped castings the method which comprises the making in an electric furnace of an iron silicid solution containing ten per cent. (10%) to sixteen .per cent. (16%) silicon and pouring said iron silicid solution while still in a molten condition into a shaped mold.

2. In the manufacture of shaped castings the method which comprises melting iron and quartz or sand in an electric arc furnace in the presence of carbon that-is employed to reduce the oxygen-in the charge whereby silicon and iron, which is of the proper proportion, can combine so as to form a composition comprising approximately ten per cent. (10%) to sixteen per cent. (16%) of silicon, and pouring the resulting composi tion while still in a molten condition into a mold so as to produce an article capable of resisting certain acids.

3. In the manufacture of castings the method which comprises the heating in an the union of the metals in the charge, the

a in the ultimate product is a compositlon comproportion of silicious material employed being such that the resulting-composition will be iron silicid containing from ten per cent. (10%) to sixteen percent. (16%) of silica, and pouring said iron silicid while still in a molten condition into a shaped mold.

4:. In the manufacture of castings, which prising a ferrous base and a content of silicon approximating from ten per cent. (10%) to sixteen per cent. (16%), by the method which comprisesheating sucha quantity of ferrous base material and silicious material in the presence of carbon providing material as will when properly heated reduce any oxygen in the ferrous base material and silicious material, supplying sufficient heat to insure the combining of any iron or re-' duced iron and any silicon or compounds of 'silicon and iron, in a molten condition,

whereby a molten bath having the required composition will result, and finally pouring the material from said bath while still in a molten condition into a shaped mold to form the desired casting. L

5. In the manufacture of castings the method which comprises charging an electric arc furnace with a mixture of ferrous base material, silicious material, as quartz, silica sand or the like, and carbon supplying material, the latter of which is provided in sufficent quantities to reduce the oxygen in the charge, thus forming heated G0 which passes through the charge, supplying sufliand also to melt the metals in the charge,

the proportion of the silicious material employed being such that the resultingcomposition Will contain from ten per cent. (10%) to sixteen per cent. (16%) of silica and pouring the composition while still in a molten condition into a shaped mold, there being maintained in the heating zone during the normal operation, of the furnace, a reducing atmosphere.

6. In the manufacture of castings the method which comprises charging a ferrous base material, silicious material and surficient carbon or carbonaceous material to reduce any oxygen in the charge, employing the electric current to supply heat to cause the carbon to perform the oxygen reducing function and to convert into molten condition the metals in the charge, collecting the resulting solution of iron and iron silicid compounds in a common receptacle and pouring the solution thus collected when in amolten condition into a mold, the proportion of the silicious material relative to the ferrous base material of the charge being such that the-resulting composltlon Wlll contain approximately from ten per cent, (10%) to sixteen per cent. (16%) of sllicon.

'7. In the manufacture of castings which are substantially Fe si or which consists of a solid solution of iron and an iron silicid approximating from ten per cent. (10%) to sixteen per cent. (16%) of the silicon, the

method which comprises charging an electric arc furnace with iron bearing material, with silicious bearing material and wlth carbon bearing material in approxlmately the following ratios: 30 pounds of silica, 20 pounds proximately 30 pounds of silica, 50 pounds of coke and 125 pounds of iron oxid, employing the electriccurrent to supply heat to cause the carbon in thecoke to reduce any oxygen in the charge and to effect a melting of coke and 88 pounds of iron scrap or apsilicid having acomposition compris ng ten per cent. (10%) to sixteen per cent; (16%) of silicon, transferring the iron silicid from the electric melting furnace to an electr c mixer, withdrawin the" molten iron silicid from the mixer an pouring it into a mold so as to produce the shaped casting desired.

9. In the manufacture of shaped castings the method which comprises the manufacturing in an electric melting furnace of an iron silicid having a composition comprising approximately ten per cent. (10%) to sixteen per cent. (16%) of silicon, transferring the iron silicid from the electric melting furnace to an electric mixer, supplying suitable slag formingmaterial which will melt and form an acid slag covering the surface of the metal in the mixer and thus prevent oxidation, Withdrawing the molten iron silicid from the mixer and pouring 'said withdrawn iron silicid into a shaped mold so as to produce the desired casting.

10. In the manufacture of shaped castings the method which comprises the producing in an electric melting furnace, by successive charges, of an iron silicid having a composition comprising approximately ten per cent. (10%) to sixteen per cent. (16%) of silicon, storing the iron silicid thus produced in a mixer and in larger quantities than the quantity produced in the furnace as the result of any one charge, maintaining the iron silicid stored in the mixer in a molten condition by electric means with which the mixer is provided, and finally withdrawing the stored material from the mixer and pouring it into a shaped mold.

11. The method which comprises forming in an electric melting furnace iron silicid having a composition comprising approximately ten per cent. (10%) to sixteen per cent. (16%) of silicon, collecting from the electric furnace the iron silicid and storing it in a mixer until the stored material in the mixer surpasses the capacity of the furnace and until enough stored material is pro-;

vided from which to make a desired shaped casting, and finally pouring said stored material in a shaped mold to form the desired casting.

This specification signed and witnessed this 17th day of December, A. D. 1917.

NAPOLEON G. PETIN OT.

Signed in the presence of ROBERT F; PETZING. 

